An update on food allergy

Newcomers in paediatric GI pathology: childhood enteropathies including very early onset monogenic IBD

Childhood enteropathies are a group of diseases causing severe chronic (>2-3 weeks) diarrhoea often starting in the first week of life with the potential for fatal complications for the affected infant. Early identification and accurate classification of childhood enteropathies are, therefore, crucial for making treatment decisions to prevent life-threatening complications. Childhood enteropathies are classified into four groups based on the underlying pathology: (i) conditions related to defective digestion, absorption and transport of nutrients and electrolytes; (ii) disorders related to enterocyte differentiation and polarization; (iii) defects of enteroendocrine cell differentiation; and (iv) disorders associated with defective modulation of intestinal immune response. While the intestinal mucosa is usually normal in enteropathies related to congenital transport or enzyme deficiencies, the intestinal biopsy in other disorders may reveal a wide range of abnormalities varying from normal villous architecture to villous atrophy and/or inflammation, or features specific to the underlying disorder including epithelial abnormalities, lipid vacuolization in the enterocytes, absence of plasma cells, lymphangiectasia, microorganisms, and mucosal eosinophilic or histiocytic infiltration. This review intends to provide an update on small intestinal biopsy findings in childhood enteropathies, the "newcomers", including very early onset monogenic inflammatory bowel disease (IBD), in particular, for the practicing pathologist.

Self-reported prevalence and risk factors associated with food hypersensitivity in Mexican young adults

BACKGROUND

Food hypersensitivity (FH) is defined as any unfavorable reaction after the ingestion, contact, or inhalation of a food. Few FH prevalence studies have been performed in the Mexican adult population.

OBJECTIVE

To determine the prevalence of self-reported FH and probable food allergy (FA) among a sample of Mexican young adults and to determine the most commonly involved foods, associated symptoms, and risk factors.

METHODS

We designed an observational, cross-sectional study in which 1,253 young adults (aged 18-25 years) born in the State of Mexico answered a questionnaire concerning FH. We obtained information on personal and familial histories of allergic diseases, the involved foods, and the subsequent adverse reactions to their consumption.

RESULTS

The prevalence of FH was 30.1% and was significantly higher in women than in men (P < .001). The prevalence of probable FA was 5.9% and was also higher in women (P = .02). Gastrointestinal symptoms were reported in 83.1% of FH cases, whereas cutaneous symptoms and oral allergy syndrome were reported in FA cases. The food groups most associated with FH were dairy products (13.2%), vegetables (10.0%), and fruits (8.0%). The food groups most associated with FA were fruits (3.0%) and seafood (1.8%). Female sex, personal history of allergic diseases, maternal history of atopic dermatitis, and parental history of urticaria were significantly associated (P < .05) with the presence of FH.

CONCLUSION

FH in young adults might be more common than previously thought, especially in women. However, further studies are needed to confirm this situation in the Mexican population.

Significance of 40-, 45-, and 48-kDa Proteins in the Moderate-to-Severe Clinical Symptoms of Buckwheat Allergy

PURPOSE

This study was aimed to investigate the relationship between the allergen components and moderate-to-severe allergic reactions in patients with buckwheat allergy.

METHODS

Fifteen patients with a history of buckwheat ingestion and a buckwheat specific IgE level≥0.35 kU/L were enrolled. They were divided into 2 groups according to clinical severity scores, with 0-1 being asymptomatic-to-mild and 2-4 being moderate-to-severe symptoms. Immunoblotting was performed to investigate IgE reactivity toward buckwheat allergens and to measure intensity of each component by using a reflective densitometer.

RESULTS

The proportions of positive band to the 16 kDa (62.5% vs 0%, P=0.026) and 40-50 kDa (87.5% vs 28.6%, P=0.041) buckwheat allergens in the grade 2-4 group were higher than those in grade 0-1 group. The level of buckwheat specific IgE of grade 2-4 group was higher than that of grade 0-1 group (41.3 kU/L vs 5.5 kU/L, P=0.037). The median optical densities (ODs) of IgE antibody binding to 40-50 kDa protein were higher in the grade 2-4 group, compared with those in the grade 0-1 group (130% OD vs 60.8% OD, P=0.037).

CONCLUSIONS

The 40-50 kDa protein is implicated as an important allergen to predict moderate-to-severe clinical symptoms in Korean children with buckwheat allergy.

Food allergy among low birthweight children in a national survey

The aim of this paper was to investigate the association between birthweight and prevalence of food allergies using a national sample of US children. Adult report of birthweight and child food allergies were obtained for years 2005-2009 from the National Health Interview Survey (NHIS), a cross-sectional household survey of the US population. A total of 51,748 children aged 0-17 years were included in the analyses representing over 73 million children. Multivariable logistic regression analyses examined associations between birthweight categories and food allergies stratified by age and gender; accounting for the complex design of NHIS. Children aged 6-12 years who were born very low birthweight (500-1,499 g) were more likely to have reported food allergy compared to referent (3,000-3,499 g), OR = 1.72; 95% CI: 1.02-2.91. However, there was no clear trend of an association between birthweight and food allergy with increasing or decreasing birthweight across all ages. Estimates were generally stronger in younger male children as compared to estimates in females of the same age group. Marginal associations for respiratory allergy (OR = 1.52; 95% CI: 1.02-2.29) and hay fever (OR = 1.54; 95% CI: 0.93-2.54) were observed among very low birthweight children aged 0-5 years. There was limited evidence for a clear association between birthweight and food allergy. Marginal associations observed in children weighing 500-1,499 g at birth support efforts to minimize preterm births and very low birthweight given the increase in pediatric food allergies and the large number of children born low birthweight each year in the US.

Prevalence of food allergy in Taiwan: a questionnaire-based survey

AIM

Food allergy is common in children and adults, and could be potentially fatal in minor groups. It is important for physicians to identify the prevalence of food allergies and to recognise common food allergens to make precise diagnosis and choose correct therapeutic approaches.

METHODS

We used a nationwide, cross-sectional, random questionnaire-based survey to estimate the self-reported and expert-screened prevalence of food allergies and to identify the common food allergens in Taiwan. In this study, the perceptional diagnosis of food allergies was screened by physicians according to descriptions of convincing symptoms and medical recordings; in the meantime, non-allergic adverse reactions to foods, including food intolerance or food avoidance, were clarified.

RESULTS

A total of 30 018 individuals who met the inclusion criteria was evaluated, and 6.95% of them were diagnosed as victims of food allergies. The prevalence was 3.44% in children under 3 years of age, 7.65% in children aged 4-18 years and 6.40% in adults respectively. About 77.33% of the food allergy population had experienced recurrent allergic attacks. Systemic reactions happened about 4.89% in food allergies group. The most commonly reported food allergen in Taiwan is seafood, including shrimp, crab, fish and mollusc. In addition, mango, milk, peanuts and eggs were also important food allergens in the general population; while milk, shellfish, peanuts and eggs were common in children.

CONCLUSIONS

Less than 10% of the Taiwan population suffers from food allergy with different allergic symptoms to variable food allergens in different age groups.

Introduction of complementary foods in infancy and atopic sensitization at the age of 5 years: timing and food diversity in a Finnish birth cohort

OBJECTIVE

To study the associations between timing and diversity of introduction of complementary foods during infancy and atopic sensitization in 5-year-old children.

METHODS

In the Finnish DIPP (type 1 diabetes prediction and prevention) birth cohort (n = 3781), data on the timing of infant feeding were collected up to the age of 2 years and serum IgE antibodies toward four food and four inhalant allergens measured at the age of 5 years. Logistic regression was used for the analyses.

RESULTS

Median duration of exclusive and total breastfeeding was 1.4 (interquartile range: 0.2-3.5) and 7.0 (4.0-11.0) months, respectively. When all the foods were studied together and adjusted for confounders, short duration of breastfeeding decreased the risk of sensitization to birch allergen; introduction of oats <5.1 months and barley <5.5 months decreased the risk of sensitization to wheat and egg allergens, and oats additionally associated with milk, timothy grass, and birch allergens. Introduction of rye <7.0 months decreased the risk of sensitization to birch allergen. Introduction of fish <6 months and egg ≤11 months decreased the risk of sensitization to all the specific allergens studied. The introduction of <3 food items at 3 months was associated with sensitization to wheat, timothy grass, and birch allergens; the introduction of 1-2 food items at 4 months and ≤4 food items at 6 months was associated with all endpoints, but house dust mite. These results were particularly evident among high-risk children when the results were stratified by atopic history, indicating the potential for reverse causality.

CONCLUSIONS

The introduction of complementary foods was consecutively done, and with respect to the timing of each food, early introduction of complementary foods may protect against atopic sensitization in childhood, particularly among high-risk children. Less food diversity as already at 3 months of age may increase the risk of atopic sensitization.

Non-dioxin-like AhR ligands in a mouse peanut allergy model

Recently, we have shown that AhR activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suppresses sensitization to peanut at least in part by inducing a functional shift toward CD4(+)CD25(+)Foxp3(+) T cells. Next to TCDD, numerous other AhR ligands have been described. In this study, we investigated the effect of three structurally different non-dioxin-like AhR ligands, e.g., 6-formylindolo[3,2-b]carbazole (FICZ), β-naphthoflavone (β-NF), and 6-methyl-1,3,8-trichlorodibenzofuran (6-MCDF), on peanut sensitization. Female C57BL/6 mice were sensitized by administering peanut extract (PE) by gavage in the presence of cholera toxin. Before and during peanut sensitization, mice were treated with FICZ, β-NF, or 6-MCDF. AhR gene transcription in duodenum and liver was investigated on day 5, even as the effect of these AhR ligands on CD4(+)CD25(+)Foxp3(+) T(reg) cells in spleen and mesenteric lymph nodes (MLNs). Mice treated with TCDD were included as a positive control. Furthermore, the murine reporter cell line H1G1.1c3 (CAFLUX) was used to investigate the possible role of metabolism of TCDD, FICZ, β-NF, and 6-MCDF on AhR activation in vitro. TCDD, but not FICZ, β-NF, and 6-MCDF, suppressed sensitization to peanut (measured by PE-specific IgE, IgG1, IgG2a and PE-induced interleukin (IL)-5, IL-10, IL-13, IL-17a, IL-22, and interferon-γ). In addition, FICZ, β-NF, and 6-MCDF treatments less effectively induced AhR gene transcription (measured by gene expression of AhR, AhRR, CYP1A1, CYP1A2, CYP1B1) compared with TCDD-treated mice. Furthermore, FICZ, β-NF and 6-MCDF did not increase the percentage of CD4(+)CD25(+)Foxp3(+) T(reg) cells in spleen and mesenteric lymph nodes compared with PE-sensitized mice, in contrast to TCDD. Inhibition of metabolism in vitro increased AhR activation. Together, these data shows that TCDD, but not FICZ, β-NF, and 6-MCDF suppresses sensitization to peanut. Differences in metabolism, AhR binding and subsequent gene transcription might explain these findings and warrant further studies to investigate the role of the AhR in food allergic responses.

The incidence and risk factors of immediate type food allergy during the first year of life in Korean infants: a birth cohort study

OBJECTIVES

We conducted this study to determine the incidence of food allergy (FA) in Korean infants and identify the risk factors of FAs during the first year of life in a birth cohort study.

METHODS

Pregnant women ≥34 weeks of gestation were enrolled in this study. Participants were asked to complete questionnaires describing basic demographic information including family history of allergic diseases. Since birth, all the babies were regularly followed up for FA symptoms through telephone interviews at 4, 8, and 12 months of age. FA was defined as a repetitive convincing history of immediate allergic reactions following the ingestion of offending food.

RESULTS & CONCLUSIONS

A total of 1177 infants and their parents completed this study. The prevalence of FA was 5.3% in infants. The three leading food allergens were hen's eggs (33/62), cow's milk (20/62) and peanut/nuts (8/62). Children with a history of maternal AD showed a significantly higher prevalence of FA (P = 0.012) [aRR = 3.17]. In addition, children who were born during autumn had a higher prevalence than those born during spring (p = 0.005) [aRR = 3.48]. In conclusion, we identified several characteristics that may influence the development of FA in the next generation, including maternal AD and autumn birth.

Activation of the aryl hydrocarbon receptor suppresses sensitization in a mouse peanut allergy model

Food allergy is an increasing health problem in Western countries. Previously, it has been shown that the intensity of food allergic reactions can be regulated by regulatory T (T(reg)) cells. In addition, it has been shown that activation of the aryl hydrocarbon receptor (AhR) regulates T-cell responses by induction of T(reg) cells. Therefore, we hypothesized that activation of the AhR pathway can suppress development of food allergic responses through the induction of T(reg) cells. This was investigated by using a mouse model for peanut allergy. C3H/HeOuJ mice (AhR(b)(-2)) were sensitized to peanut by administering peanut extract (PE) by gavage in the presence of cholera toxin and were treated with the prototypical AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (0.6, 1.7, 5, and 15 μg/kg body weight) on days 3 and 11 orally. The functional role of CD4(+)CD25(+)Foxp3(+) T(reg) cells was investigated by depleting these cells with anti-CD25 mAb during sensitization to PE. TCDD treatment dose dependently suppressed sensitization to peanut (PE-specific IgE, IgG1, and IgG2a and PE-induced IL-5, IL-10, and IL-13, respectively). The percentage, but not the number, of CD4(+)CD25(+)Foxp3(+) T(reg) cells dose dependently increased by AhR activation in both spleen and mesenteric lymph nodes. Depletion of CD4(+)CD25(+)Foxp3(+) T(reg) cells markedly reversed the suppressive effect of TCDD on PE-specific antibody levels and PE-induced IL-5, IL-10, and IL-13 cytokine production. Present data demonstrate for the first time that activation of the AhR by TCDD suppressed the development of Th2-mediated food allergic responses. A functional shift within the CD4(+) cell population toward CD4(+)CD25(+)Foxp3(+) T(reg) cells appeared to underlie this effect. This suggests that the AhR pathway might provide potential therapeutic targets to treat food allergic diseases.

Anaphylaxis to hyperallergenic functional foods

Background

Food allergy can cause life threatening reactions. Currently, patients with severe food allergy are advised to avoid foods which provoke allergic reactions. This has become increasingly difficult as food proteins are being added to a broader range of consumer products.

Patients and methods

Here we describe our investigations into the allergenicity of a new drink when two cow's milk allergic children suffered anaphylaxis after consuming Wh₂ole^®.

Results

Our studies have shown that in comparison with cow's milk, Wh₂ole^® contains at least three times the concentration of β-lactoglobulin. β-lactoglobulin is one of the dominant allergens in bovine milk.

Conclusions

These studies have shown that modern technology allows the creation of "hyperallergenic" foods. These products have the potential to cause severe reactions in milk allergic persons. Avoiding inadvertent exposure is the shared responsibility of allergic consumers, regulatory authorities and the food industry.

Enteropathies of Infancy and Childhood

Intestinal biopsies constitute an ever-increasing portion of the pathologist's workload, accounting for nearly two-thirds of specimens accessioned yearly by the pathology department at The Children's Hospital of Philadelphia. The widespread use of endoscopy and gastrointestinal biopsies in current clinical practice presents the pathologist with a diversity of intestinal mucosal appearances corresponding to disease states of variable clinical severity, requiring close collaboration between clinician and pathologist for optimal interpretation. Many of the entities resulting in severe diarrhea of infancy have been recognized only in the last several decades, and although rare, the study of these disorders, especially when combined with the powerful methods of present-day genetics and molecular biology, has afforded important insights into enterocyte development and function, and intestinal immunity and tolerance. Other conditions once considered infrequent, such as celiac disease, have now been recognized to be much more common and can present with a wide range of pathologic features.

Immunotherapy for food allergy

Although the current standard care for patients with food allergy is based on avoidance of the trigger foods with hope of possible gain of tolerance, increasing number of studies have shown that oral immunotherapy is a promising approach. Understanding the transcutaneous sensitization and oral immune tolerance to food antigens has shifted focus of treatment and prevention. However, more studies are warranted to elucidate the underlying mechanisms and to clarify the indication criteria to which type of patients this therapy should be applied. Easy and uncontrolled use of elimination diets for atopic dermatitis might have increased and exacerbated food allergy, and thorough innovation of our whole concept for food allergy is now required.